Warehouse storage of goods and articles has been known for many years. Due to the large amounts of goods that can be stored inside of a warehouse, attempts have been made to create various systems and methods to track warehouse inventory and effectively retrieve particular goods from the warehouse to satisfy customer orders or fulfill other needs such as storage and retrieval of goods in a cargo vessel. Traditionally, manpower was used to store goods in a warehouse type, multi-level system of racks and to locate and retrieve specific items stored therein.
The warehousing of goods soon became more sophisticated, in that, goods were being stored in multi-level racks that stretched beyond the reach of persons standing on the ground level. With this new storing scheme, elevating equipment, such as, forklifts were needed to elevate the manpower to the desired level of the warehouse rack to store or retrieve the goods needed, for example, to fill the orders of awaiting customers. The problem with this traditional warehouse operation is that many personnel were needed to operate warehouses having high storage capacities. In addition, human error resulted in goods being stored in and retrieved from the wrong location in the warehouse which could be costly for a company to correct. Warehouse designers attempted to use elevators to overcome the problem of storing and retrieving multi-level stacks of goods, however, certain problems still limited warehouse production and operation. These include the limited amount of weight that one person could lift.
The industry has recognized that, in order to increase warehouse production and efficiency, an improved retrieval and storage system would be necessary to reduce the human element. By using robots and other machines to reduce the amount of manual labor required, a higher volume of goods could be stored or retrieved in less time and/or with less cost.
One attempt to automate storage and retrieval for warehouse applications is disclosed in U.S. Pat. No. 4,971,507 to Wegglaar which discloses a storage system wherein a carriage extendable from a fork-lift truck moves within rails provided in a multi-tiered rack to deposit or retrieve palletized goods. The carriage is able to access each level of the multi-tiered rack using a vertically extending mast on the fork-lift truck. Due to the limited extension of the mast, however, the height of the storage rack must be restricted. In addition, the system requires a person to control and operate the fork-lift truck and carriage.
A further means of automating warehouse storage and retrieval is found in U.S. Pat. No. 3,924,300 to Hilger et al. which discloses a shuttle car used to transfer an article from one station to another by a mechanism which has a vertically movable bed portion and may be elevated to pick-up an article or load and lowered to deposit the same article or load.
Other automated storage and retrieval systems used in warehouse environments include U.S. Pat. No. 5,333,982 to Tanizawa which teaches a plurality of electrically driven cargo carriers that run on multi-level routes disposed one over another between two rows of opposing assemblies of cargo storage shelves and U.S. Pat. No. 4,395,181 to Loomer which discloses an automated storage system comprising a vehicle for transporting loaded pallets within a plurality of tracks that form a storage rack. The disclosed vehicle in Loomer comprises extendable lift mechanisms for elevating pallets above the level of the tracks during vehicle traversal and for lowering the pallets onto support surfaces formed on the tracks for storage.
The problem with the automated systems disclosed in Loomer, Tanizawa et al. and Hilger et al. is that each system uses a separate cargo carrier or shuttle for each level of a storage rack resulting in a large number of required shuttles for effective operation. Due to their complexity, these types of systems are costly to manufacture, operate and maintain. In addition, if one or more of the cars employed in the above systems breaks down, the warehouse operator would have to manually access the goods serviced by that vehicle.
An improvement on the above automated systems is found in U.S. Pat. No. 5,379,229 to Parsons et al. which discloses an automated storage and retrieval system having a single storage transport able to access different tiers of a multi-tiered storage rack to deposit or retrieve objects stored therein. The system, however, is limited to depositing and retrieving small objects and does not include the type of supports required for manipulating large cases of goods or articles normally stored on a pallet.
U.S. Pat. No. 3,817,406 to Sawada et al., U.S. Pat. No. 4,252,217 to Benjamin, and U.S. Pat. No. 4,459,078 to Chiantella et al. disclose automated warehousing systems that employ a crane device in combination with a movable shuttle that is able to access each level of a storage rack. The designs of these automated warehousing systems do not require the amount of manpower necessary to operate effectively the Wegglaar system discussed above. Benjamin, however, does require an operator to control the disclosed crane device. Moreover, all of the above-noted systems appear to be limited in the amount of goods that can be transported in a single "run."
In view of the above devices and their limitations, there remains a need for an automated storage and retrieval system that is not restricted to one movable shuttle per tier and is capable of transporting a large amount of goods from a single tier. To facilitate the ability to transport large loads, there is a further need for a rail system that can accommodate multiple shuttles and can be used as a "drip pan" to collect any leakage from the goods stored on the multi-tiered storage rack.
A system design that improves upon the references cited above is provided in International Application No. PCT/EP95/00738 filed on Mar. 1, 1995 to Upmeyer which shows a pallet shelf system having multiple tiers and comprising supporting and running guides for supporting pallets thereon and a pallet transporting car movable within the supporting and running guides for depositing and retrieving palletized goods. In an alternative embodiment of Upmeyer, the supporting and running guides form a running tub to provide air circulation to the palletized goods, such as perishable fruit. Two pallet transporting cars may be coupled together in the Upmeyer system for movement within two adjacent channels formed by a pair of touching inner support rails for supporting a single pallet and for forming the inner guides for the coupled pallet transporting cars.
Although the Upmeyer system improves upon the systems discussed above, the inventor of the present invention has identified a need in the industry for an automated storage system that is able to receive, store and retrieve high volumes of goods efficiently without the need for pallets. Pallets are cumbersome and take up space within the warehouse that can otherwise be used effectively. For example, when articles are completely removed or "picked" from a pallet, the pallet must be manually moved to a designated return lane for later usage. The time needed to manipulate pallets decreases the efficiency of warehouse operation. Furthermore, pallets add to system installation costs and pallets may break and require replacement which adds still further to the cost of maintaining warehouse operation. In addition, there is a need for a support rail design that acts as a "drip pan" to collect leakage from stored goods such as dairy cases. There is also a need for an automated storage system wherein multiple shuttles may be used to facilitate transporting loads of varying sizes whether palletized or not. Furthermore, there is a need for an automated storage system that is able to receive, store and retrieve stackable goods such as dairy cases in a cost effective, efficient and reliable manner. To this end, there is also a need for such an automated storage system that prevents stacked goods such as dairy cases, from tilting, tipping or misaligning when the stacked goods are stored within and transported through a storage lane.